PLATE LXX. 



Sternoptyx diaphana. 



Fig. 15. The fish seen from the side, natural size; drawn from a spirit specimen. 



(I, Ventral luminous organ ; b, anterior, c, posterior lateral luminous organs ; d, anal 

 membrane ; e, submaxillary phosphorescent gland. 



Fig. 16. Submaxillary phosphorescent gland, seen e?iyace. x 4. 



a, Mouth. 



Fig. 17. Ventral luminous organ, seen from below. x 2. 

 a, Ventral fins. 



Fig. 18. Ventral luminous organ, longitudinal section, parallel to the median 

 plane of the fish to the side of the mid rib. x 2. 

 ", Central ranal ; b, parabolic cups. 



Fig. 1 9. Ventral luminous organ, outer surface. x 20. 

 a, Projecting mid rib ; ft, pigment-mantle. 



Fig. 20. Transverse section of the nnterior end of the ventrnl luminous organ. 

 X 100. 



n. Projecting cartilaginous mid rib ; h, cartilage thread; c, crystalline spicules arranged 

 longitudinally so as to reflect the light ; '/, pigment-mantle ; e, main canal ; 

 /, parabolic, paired organs, the apertures of which are covered by a transparent 

 cornea-like membrane ; g, transparent connective tissue surrounding the phos- 

 phorescent tissue. 



Fig. 21. Transverse section through the anterior end of the ventral luminou.'< 

 orojan. x .50. 



a, Pigment-mantle ; b, light-reflecting layer of spicules ; r, transparent connective 

 tissue ; d, phosphorescent tissue ; e, transparent outer skin. 



Fig. 22. Postero-lateral luminous organ, seen from the outside. x .30. 

 Fig. 23. Longitudinal section of the postero-lateral luminous organ. x 50. 



a, Spicules forming a light-reflecting layer ; b, pigment-mantle ; c, large highly 

 stainable cells at the entrance of the luminous sac ; d, gland-tubes. 



Fig. 24. Transverse section through the hemiparabolic reflectors of the postero- 

 lateral luminous organ. x 50. 



", Spicules forming a light-reflecting layer ; ft, pigment-mantle ; c, transparent con- 

 nective tissue ; d, gland-tubes. 



